JP4631533B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a radio communication apparatus that receives and processes an ultra wide band (UWB) signal in which information is placed on a very weak impulse train using an ultra wide band, and in particular, to a transmitter. The present invention relates to a wireless communication apparatus that measures a distance between objects using UWB communication of a weak impulse train.

  More particularly, the present invention relates to a wireless communication apparatus that determines the position of a transmitter using reception timing information of a UWB signal from a transmitter, and in particular, performs reception processing by performing digital processing on a received UWB signal. The present invention relates to a wireless communication apparatus that performs detection.

  The demand for wireless LAN systems has increased significantly as the speed and price of wireless LAN systems have decreased. In particular, the introduction of a personal area network (PAN) has been studied in order to construct a small-scale wireless network between a plurality of electronic devices existing around a person and perform information communication. For example, different radio communication systems and radio communication apparatuses are defined using frequency bands that do not require a license from a supervisory agency, such as 2.4 GHz band and 5 GHz band.

  In recent years, a method called “ultra-wide band (UWB) communication” for performing wireless communication by placing information on a very weak impulse train has attracted attention as a wireless communication system that realizes short-range ultrahigh-speed transmission, and its practical use. Is expected.

  In the United States, FCC (Federal Communication Commission) relaxed regulations on the UWB system in February 2002 (see, for example, Non-Patent Document 1). The contents of the deregulation allow the emission of radio waves with an output of −41.3 [dBm] from 3.1 GHz to 10.6 GHz. Currently, in IEEE802.15.3 and the like, a data transmission method having a packet structure including a preamble has been devised as an access control method for ultra-wideband communication (see, for example, Non-Patent Document 2).

  On the other hand, the UWB system has a high time resolution by using ultra-fine pulses, and can perform “ranging” for radar and positioning using this property. In particular, recent UWB communication can have both high-speed data transmission exceeding 100 Mbps and the original ranging function (see, for example, Patent Document 1).

  In the future, WPAN (Wireless Personal Access Network) of near field communication represented by UWB is expected to be installed in all home appliances and CE (Consumer Electronics) devices. Therefore, apart from high-speed data transmission, it is considered that the use of position information by ranging, such as navigation and near field communication (NFC), may create added value of radio, and distance measurement together with high-speed data transmission. It is considered desirable to implement the function.

  FIG. 14 schematically shows a configuration of a ranging system using UWB communication. The system shown in the figure assumes that UWB communication is mainly used for distance measurement rather than data transmission, and the transmitter is composed of a small device such as an IC chip or an IC tag, and a UWB signal carrying a known pattern. To send. And the receiver which exists in the circumference | surroundings of this transmitter detects the reception timing information of the received UWB signal, and detects the distance to a transmitter, and its position.

  In order to detect the distance or the position on the receiver side as described above, it is necessary to acquire accurate reception timing information of the UWB signal.

  For example, a technique for detecting reception timing information by performing analog processing on a UWB signal has been proposed (for example, see Non-Patent Document 3). As shown in FIG. 15, the circuit configuration includes an antenna unit, a template generation circuit, a loop filter, and an analog circuit including a clock generation circuit. The signal received by the antenna unit is correlated with the signal generated by the template generation circuit, the reception timing is detected from the correlation value by a loop filter, and the reception timing is corrected to the clock generation circuit.

  However, in order to process a high-frequency signal such as a UWB signal with analog parts, a large number of high-precision analog parts are required, which increases the cost of the receiver. Further, an increase in mounting error is expected, and it is difficult to design a high-frequency circuit.

  When the reception timing detection for a UWB wideband signal is performed by an analog circuit, it is impossible to avoid complication of the configuration of the delay circuit and the frequency synthesis circuit. As a result, a method of detecting the reception timing by performing digital processing on the received UWB signal is recalled. In this case, the problem is how to set the sample rate and resolution (number of bits) in the A / D converter.

  For example, a UWB receiver that undersamples a high-frequency UWB signal has been proposed (see, for example, Non-Patent Document 4). In this UWB receiver, an A / D converter having a 1-bit resolution is used, and the analog circuit is configured to correlate on the frequency axis using a number of analog filter banks. It becomes complicated. The UWB receiver itself does not have a distance measuring function.

  Further, there has been proposed a system that performs digital processing after down-converting the frequency of a received signal and detects reception timing information (see, for example, Non-Patent Document 5). As shown in FIG. 16, the system includes an antenna unit for digitally processing a narrowband CDMA signal, an A / D converter, and a timing detection circuit. A signal received by the antenna unit is converted into a baseband signal, converted into a digital signal at a chip rate by an A / D converter, and reception timing is detected by a timing detection circuit.

  As described above, the conventional system for detecting the reception timing by the digital circuit assumes low-speed A / D conversion and digital processing based on the chip rate. For this reason, the timing detection circuit is configured as shown in FIG. Since the UWB signal has a shorter symbol length than narrowband CDMA, high-speed A / D conversion and high-speed digital processing are required, and it is difficult to perform complicated digital processing, which increases power consumption and mounting area. is expected.

  With the circuit configuration shown in FIG. 16, it is not easy to realize a system that performs digital processing after down-converting the frequency of the received signal. Since a UWB signal does not use a carrier wave, it is not easy to convert it to a baseband signal. Therefore, a high-speed A / D converter and high-speed digital processing are required to perform processing with a high frequency. It is difficult to perform complex digital processing, which leads to an increase in power consumption and mounting area. Further, if a down-conversion circuit using an analog circuit is inserted, the cost of the receiver increases.

  FIG. 18 shows another conventional example relating to a system for digitally processing a received signal to detect reception timing. This system is composed of an antenna unit, an A / D converter, an averaging filter, and a timing detection circuit. A signal received by the antenna unit is converted into a digital signal by an A / D converter, and an averaging filter is used. After pre-processing, the reception timing is detected by the timing detection circuit. Here, the resolution and speed are determined by the noise level and band of the received signal handled by the A / D converter. In general, a method of detecting timing using a high-resolution and high-speed A / D converter is known (for example, see Non-Patent Document 6).

  In the system shown in FIG. 18, an A / D converter having 1.5 bits or more is used. In this case, samples having positive and negative values are input to the averaging filter. FIG. 19 shows a configuration example of an averaging filter used conventionally. In order to average using sample values having positive and negative values output from the A / D converter, an ALU (arithmetic logic circuit) capable of adding positive and negative values and an operation result are temporarily stored. This register is required. Further, since averaging is performed in parallel in units of received frames, it is necessary to drive N ALUs in parallel (where N is the number of samples in one frame time). This means that the circuit design is difficult and the power consumption increases when the sample rate is high.

  That is, it is not easy to configure a system that detects the reception timing after digitally processing a received UWB signal using a high-resolution and high-speed A / D converter as shown in FIG. A high-resolution A / D converter is not practical as a portable device, whether it is an experimental machine or not. In this case, a high-speed averaging filter is required, which increases the cost of the receiver. In addition, high cost and high power consumption of the A / D converter itself are also problematic.

  Also, a proposal has been made for a UWB device that can reduce power consumption and shorten signal acquisition time not only for communication but also for positioning and ranging (for example, Patent Documents). 2). In this UWB device, the width of the pulse carried on the UWB signal is widened by passing it through a low-pass filter, thereby enabling digitalization by an A / D converter having a low sample rate. However, there is a problem that if the received waveform is disturbed due to multipath below the A / D conversion sample rate, the received waveform is affected. Also, when A / D converting a long pulse, the received signal is input to multiple correlators and the peak timing is changed from each correlator output to change the sample timing. There is also a problem that the positioning distance is weakly and transparently reduced.

JP 2002-51001 A JP 2005-51466 A Sasaki Shigenobu, Ikegami Tetsufumi, and Koda Toshitoshi "International Conference on UWB System and Technology (UWBST2002)" (SST2002-19, July 2002) http: // grouper. iee. org / groups / 802/15 / pub / SG4a. html Y. Shimizu and Y.M. Sanada, "Accuracy of Relative Distance Measurement with Ultra Wideband System" (IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, vol.J86-A, no.12, pp.1310-1319, Dec.2003 (in Japan)) Hyun-Jin Lee, Dong Sam Ha, and Hyng-Soo Lee, “Toward Digital UWB Radios: Part I-Frequency Domain UWB Receiver W 1U U R. D. Gaudenzi, M .; Luise, and R.M. Viola, “A digital chip timing recovery for band limited direct-sequence spread-spectrum signals” (IEEE Trans Commun., Vol COM-41, pp. 1760-1917). Y. Shimizu and Y.M. Sanada, "Relative Distance Measurement with Ultra Wideband System with High Speed 1.5bit A / D Converter" (Proc. Of the Seventh International Symposium on Wireless Personal Multimedia Communications, vol.1, pp.50-54, Abano Terme, Italy, (Sept, 2004)

  An object of the present invention is to provide an excellent wireless communication apparatus capable of suitably measuring a distance between objects using UWB communication of a weak impulse train with a transmitter. is there.

  A further object of the present invention is to provide an excellent wireless communication apparatus capable of detecting reception timing by performing digital processing on a received UWB signal.

  A further object of the present invention is to provide excellent wireless communication in which a received UWB signal can be digitally processed using an A / D converter having an appropriate sample rate and resolution to obtain accurate reception timing information. To provide an apparatus.

The present invention has been made in consideration of the above problems, and a first aspect thereof is a wireless communication apparatus that receives a UWB signal in which a pulse is placed on a wide band,
An antenna unit for receiving a UWB signal;
A 1-bit A / D converter that converts a signal received by the antenna unit into a digital signal;
An N parallel counter that counts in parallel the number of occurrences of 1 for every N samples and outputs in units of frames (N is the number of samples in one frame time);
A timing detection unit that detects the reception timing of a frame based on the number of occurrences of 1 counted every N samples;
A wireless communication device comprising:

  In the UWB communication system, use of position information by distance measurement is being studied separately from high-speed data transmission. In order to realize a highly accurate ranging function, it is necessary to acquire accurate reception timing information of the UWB signal on the UWB receiver side.

  When the reception timing of the UWB signal is detected by an analog circuit, the configuration of the delay circuit and the frequency synthesis circuit cannot be complicated. For this reason, it is considered that a method of detecting the reception timing by performing digital processing on the received UWB signal is preferable. In this case, what is the sample rate and resolution (number of bits) in the A / D converter? It becomes a problem how to set.

  The present inventors consider that in a UWB communication system mainly used for distance measurement, an A / D converter can be sufficiently used even if the resolution is low if the sample rate is high.

  The wireless communication apparatus according to the first aspect of the present invention includes a 1-bit A / D converter and detects reception timing by performing digital processing on a received UWB signal using an N parallel counter. .

  The antenna unit includes one or more antenna elements, a filter, an LNA (low noise amplifier), and the like. Since the wireless communication device is configured to detect a signal interval and a no-signal interval, the antenna serving as a communication path is not particularly limited. The 1-bit A / D converter receives a signal received from the antenna unit, compares the signal strength with a predetermined threshold value, and converts the signal into a binary digital signal. The conversion speed of the A / D converter is determined based on the communication method to be used and the symbol length. The output of the A / D converter is generally a digital signal with a high sample rate. When this digital signal is input, the N parallel counter counts the number of occurrences of 1 for every N samples in parallel and outputs it in units of frames. Then, the timing detection circuit detects the reception timing of the frame based on the counted number of occurrences of 1.

  Although the sample rate of the digital signal after A / D conversion is high, the digital signal is already a low sample rate in the N parallel counter. Therefore, the statistical filter processing in the timing detection unit is digital signal processing, and in many cases, processing is performed using a DSP (Digital Signal Processor) or FPGA (Field Programmable Gate Array) similar to other digital signal processing.

  As described above, according to the wireless communication apparatus according to the first aspect of the present invention, since the reception timing is detected using the comparator (1-bit A / D converter) and the N parallel counter, a high resolution A / D It is not necessary to use a D converter or a high-speed N parallel ALU, and it is possible to realize cost reduction, size reduction, power saving, and the like of the receiver.

A second aspect of the present invention is a wireless communication device that receives a UWB signal in which a pulse is placed on a wideband,
An antenna unit for receiving a UWB signal;
An A / D converter that converts a received signal from the antenna unit into a digital signal by oversampling;
A timing detection unit that detects reception timing based on a digital signal output from the A / D conversion;
A wireless communication device comprising:

  The wireless communication apparatus according to the second aspect of the present invention includes a high-speed oversampling A / D converter, and detects reception timing by performing digital processing on the received UWB signal. The oversampling A / D converter is, for example, a 1-bit A / D converter that converts a signal into a digital signal, and an N parallel counter that counts the number of occurrences of 1 every N samples in parallel and outputs the number in units of frames Can be configured.

  The antenna unit includes one or more antenna elements and a filter LNA (low noise amplifier). Since the wireless communication device is configured to detect a signal interval and a no-signal interval, the antenna serving as a communication path is not particularly limited. The A / D converter converts the received signal of the antenna unit into a digital signal by oversampling at a high sample rate. The conversion speed of the A / D converter is determined based on the communication method to be used. The timing detection circuit detects the reception timing from the output of the A / D converter.

  Since the output of the A / D converter is generally a digital signal with a high sample rate, reception timing cannot simply be detected by the existing digital CDMA receiver system. Therefore, in the second aspect of the present invention, a timing detection circuit is constituted by a two-stage matched filter of a chip matched filter and a frame matched filter, and reception timing is obtained using a DSP or FPGA similar to other digital signal processing. It was made possible to perform the detection process.

  The chip matched filter at the previous stage calculates the correlation between the input digital reception signal and a predetermined template signal. If this correlation value exceeds the threshold value, it is recognized that a correct transmission pulse signal has arrived, and the presence / absence of a pulse and how many chips the reception timing has shifted are output to the subsequent frame matched filter. Further, the subsequent frame matched filter determines whether the received frame is correct or not by taking a correlation value with the spreading code. When it is determined that the received frame is correct, the reception timing is finally output. On the other hand, if it is determined that the received frame is incorrect, it is determined that the pulse detection is not successful, and feedback is performed so as to change the threshold value for the chip matched filter. As described above, it is easy to mount the timing detection circuit only by providing two matched filters, and the timing detection accuracy can be improved by performing the two-stage check.

  That is, according to the radio communication apparatus according to the second aspect of the present invention, the reception timing is detected using the high-speed A / D converter, the chip matched filter, and the frame matched filter. The function does not need to be configured by an analog circuit, and can be realized by simple digital processing.

  ADVANTAGE OF THE INVENTION According to this invention, the outstanding radio | wireless communication apparatus which can detect a reception timing by performing a digital process to the received UWB signal can be provided.

  In addition, according to the present invention, it is possible to digitally process a received UWB signal using an A / D converter having an appropriate sample rate and resolution, and to obtain accurate reception timing information. A communication device can be provided.

  According to the wireless communication apparatus of the present invention, since the reception timing is detected using the comparator (1-bit A / D converter) and the N parallel counter, a high resolution A / D converter and a high speed N parallel are used. There is no need to use an ALU, and cost reduction, size reduction, power saving, etc. of the receiver can be realized.

  Further, according to the wireless communication apparatus of the present invention, reception timing is detected using a high-speed A / D converter, a chip matched filter, and a frame matched filter. Therefore, it is not necessary to configure the reception timing detection function with an analog circuit, and it can be realized by simple digital processing, so that it is possible to realize cost reduction, size reduction, power saving, and the like of the receiver.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention relates to a wireless communication apparatus that receives a UWB signal in which a pulse is placed on a wide band, and in particular, measures a distance between objects using UWB communication of a weak impulse train with a transmitter. It is related with the radio | wireless communication apparatus which performs.

  When the reception timing of the UWB signal is detected by an analog circuit, the configuration of the delay circuit and the frequency synthesis circuit cannot be complicated. For this reason, it is considered that a method of detecting the reception timing by performing digital processing on the received UWB signal is preferable. In this case, what is the sample rate and resolution (number of bits) in the A / D converter? It becomes a problem how to set. On the other hand, the present inventors consider that, in a UWB communication system mainly used for ranging, an A / D converter can be sufficiently used even if the resolution is low if the sample rate is high.

  FIG. 1 schematically shows the configuration of a wireless communication apparatus according to an embodiment of the present invention. The wireless communication apparatus 10 operates as a UWB receiver, includes a 1-bit A / D converter, and detects reception timing by performing digital processing on a received UWB signal using an N parallel counter. Is.

  As illustrated, the wireless communication apparatus 10 includes an antenna element 11, a filter 12, an LNA (low noise amplifier) 13, a comparator 14, a counter 15, and a timing detection unit 16.

  The antenna unit includes one or more antenna elements 11, a filter 12, and an LNA 13. Since the wireless communication device is configured to detect a signal interval and a no-signal interval, the antenna serving as a communication path is not particularly limited.

  The comparator 14 operates as a 1-bit A / D converter, receives the received signal from the antenna unit, compares the signal intensity with a predetermined threshold value, and converts the signal into a binary digital signal. That is, sample data is limited to {0, 1}. The conversion speed of A / D conversion is determined based on the communication method to be used, but its output is generally a digital signal with a high sample rate.

  The counter 15 is composed of N parallel counters as shown in FIG. 2. When the digital signal of the comparator 14 is input, the number of occurrences of 1 for every N samples is counted in parallel and output in units of frames. To do. Then, the timing detection unit 16 detects the reception timing of the frame based on the counted number of occurrences of 1.

  Since the sample value input from the comparator 14 is limited to {0, 1}, it is not necessary to use an ALU and a register, and it is only necessary to provide a parallel counter 15 that counts the number of times the sample input becomes “1”. . Then, although the sample rate of the digital signal after A / D conversion is high, the N parallel counter 15 turns the digital signal into a low sample rate. Since there is no need to exchange data with the register and there is no need for a complement generation circuit or the like necessary for addition of negative numbers, the implementation of the counter circuit is easy. Therefore, both processing speed and power consumption are expected to improve.

  Next, the reception timing detection operation in the wireless communication apparatus 10 shown in FIG. 1 will be described with reference to FIGS.

  FIG. 3 shows an example of a received signal in UWB communication. As shown, a pulse wave is placed on a wide band.

  The received signal output from the antenna unit is input to the comparator 14. When there is no thermal noise, the received frame is A / D converted into binary sample data as shown in FIG.

Here, if one frame is sampled at N sample points by the comparator 14, it is a region where N _P samples obtained by sampling the positive signal components in FIG. 3 becomes 1 in FIG. 4. Further, a region where N _G obtained by sampling the guard interval in the absence of negative signal component N _M samples and a signal obtained by sampling the can in FIG. 3 becomes 0 in Fig.

On the other hand, FIG. 5 shows an example in which the received frame is A / D converted when thermal noise is included in the received signal. Since thermal noise follows a Gaussian distribution, the N _p and N _M regions having signal components are not easily affected, but are affected in the N _G region having no signal components. In the illustrated example, it is assumed that N _G / 2 pieces of 1 is output at the N _G.

  The output of the comparator 14 is input to an N parallel counter 15, and the number of occurrences of 1 for every N samples is counted. For example, when counting for L (L = 4) frames is performed as shown in FIG. 5, the output is as shown in FIG. Here, the maximum value of the output of the counter is L.

Next, the output of the N parallel counter 15 is input to the timing detection unit 16. It is expected that the output of the N parallel counter 15 is L / 2 in the N _G region where the thermal noise directly affects, and L and 0 in the N _p and N _M regions where there are signal components, respectively. Therefore, as shown in FIG. 6, two threshold values of 3L / 4 and L / 4 are set. If the counter value is 3L / 4 or more, 1 is set, -1 is set if L / 4 or less, 0 is set otherwise. Make a decision. Thereby, as shown in FIG. 7, a valid frame can be recognized and reception timing can be detected.

  FIG. 8 schematically shows the configuration of a wireless communication apparatus according to another embodiment of the present invention. The wireless communication device 20 operates as a UWB receiver, includes a high-speed oversampling A / D converter, and detects reception timing by performing digital processing on the received UWB signal.

  As illustrated, the wireless communication device 20 includes an antenna element 21, a filter 22, an LNA 23, an A / D converter 24, and a timing detection unit 25.

  The antenna unit includes one or more antenna elements 21, a filter 22, and an LNA 23. Since the wireless communication device is configured to detect a signal interval and a no-signal interval, the antenna serving as a communication path is not particularly limited.

  The A / D converter 24 performs oversampling at a high sample rate. For example, a 1-bit A / D converter that converts a signal into a digital signal and a number in which 1 appears every N samples are parallelized. An N parallel counter (see FIG. 2) that counts and outputs in units of frames can be used.

  The output of the A / D converter 24 is input to the timing detection unit 25, and reception timing is detected. However, since this A / D conversion output is a digital signal with a high sample rate, reception timing cannot simply be detected by the existing digital CDMA receiver system. Therefore, in the wireless communication device 20 according to the present embodiment, the timing detection unit 25 is configured by a two-stage matched filter of a chip matched filter 26 and a frame matched filter 27 as shown in FIG. The reception timing detection process can be performed using the same DSP or FPGA.

  The preceding chip matched filter 26 calculates a correlation between the input digital reception signal and a predetermined template signal. If this correlation value exceeds the threshold value, it is recognized that a correct transmission pulse signal has arrived, and the presence / absence of a pulse and how many chips the reception timing has shifted are output to the frame matched filter 27 at the subsequent stage.

  The subsequent frame matched filter 27 determines whether the received frame is correct by taking a correlation value with the spreading code. When it is determined that the received frame is correct, the reception timing is finally output. On the other hand, if it is determined that the received frame is incorrect, it is determined that the pulse detection is not successful, and feedback is performed to the chip matched filter 26 so as to change the threshold value.

  As described above, the timing detection circuit can be easily mounted only by including the two matched filters 26 to 27, and the timing detection accuracy can be improved by performing the two-stage check.

  Next, the reception timing detection operation in the wireless communication apparatus 20 shown in FIG. 8 will be described with reference to FIGS.

  The transmitter follows a spreading code, and transmits a pulse when the spreading code is 1, and does not transmit a pulse otherwise. FIG. 10 shows a waveform of a pulse signal received by the wireless communication device 20 as a receiver when there is no thermal noise output from the antenna unit. When the received pulse signal mixed with thermal noise is A / D converted, the result is as shown in FIG.

  As shown in FIG. 12, the template signal used by the chip matched filter 26 is 1 for a positive signal of an ideal received pulse signal, −1 for a negative signal, and 0 for no signal. The chip matched filter 26 correlates the digital received pulse signal waveform shown in FIG. 11 and the template waveform shown in FIG. 12, and determines the presence or absence of a pulse depending on whether the correlation value exceeds a predetermined threshold value α.

FIG. 13 illustrates the manner in which the receiving chip position of the pulse is confirmed. From pulse position d _n which is estimated from the received frame of plain-speaking until it finds a valid pulse back and forth to search for the chip. When a valid pulse is found, the chip matched filter 26 outputs that the received frame signal is 1 and the reception timing shift d _s .

Next, the frame matched filter 27 determines whether the detected received frame information is correct by obtaining a correlation value between the received frame signal and the spread code. If the calculated correlation value becomes the spreading code length, it is determined that the received frame information is correct. In this case, a reception timing shift d _s is output. In other cases, it is determined that the detection of the received frame information is incorrect, and the change of the threshold value α is fed back to the chip matched filter 26. Thereby, a valid frame is recognized and a received frame is detected.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiment without departing from the gist of the present invention. That is, the present invention has been disclosed in the form of exemplification, and the contents described in the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims should be taken into consideration.

FIG. 1 is a diagram schematically illustrating a hardware configuration of a wireless communication apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the parallel counter 15 in the wireless communication apparatus 10 shown in FIG. FIG. 3 is a diagram illustrating an example of a received frame. FIG. 4 is a diagram showing an example of an effective frame when there is no thermal noise. FIG. 5 is a diagram illustrating an example of a directed frame group when there is thermal noise. FIG. 6 is a diagram illustrating an output example of the N parallel counter. FIG. 7 is a diagram illustrating an example of an effective frame recognized by the timing detection unit 16. FIG. 8 is a diagram schematically illustrating a hardware configuration of a wireless communication device 20 according to another embodiment of the present invention. FIG. 9 is a diagram showing an internal configuration of the timing detection unit 25 in the wireless communication apparatus 20 shown in FIG. FIG. 10 is a diagram showing a received pulse waveform. FIG. 11 is a diagram illustrating a waveform of a digital reception pulse signal. FIG. 12 is a diagram showing a template waveform. FIG. 13 is a diagram showing a state of pulse detection. FIG. 14 is a diagram schematically showing the configuration of a ranging system using UWB communication. FIG. 15 is a diagram illustrating a configuration example of a system that detects reception timing information by performing analog processing on a UWB signal. FIG. 16 is a diagram illustrating a configuration example of a system that detects reception timing information by performing digital processing after down-converting the frequency of a reception signal. FIG. 17 is a diagram showing a configuration example of a timing detection circuit in the system shown in FIG. FIG. 18 is a diagram showing another conventional example related to a system for digitally processing a received signal to detect reception timing. FIG. 19 is a diagram illustrating a configuration example of the averaging filter.

Explanation of symbols

10: Wireless communication apparatus (embodiment of the present invention)
11 ... Antenna element 12 ... Filter 13 ... LNA
DESCRIPTION OF SYMBOLS 14 ... Comparator 15 ... N parallel counter 16 ... Timing detection part 20 ... Wireless communication apparatus (other embodiment of this invention)
21 ... Antenna element 22 ... Filter 23 ... LNA
24 ... Oversampling A / D converter 25 ... Timing detector 26 ... Chip matched filter 27 ... Frame matched filter

Claims (3)

A wireless communication device for receiving a UWB signal with a pulse on a wideband,
An antenna unit for receiving a UWB signal;
An oversampling A / D converter that converts a received signal from the antenna unit into a digital signal by oversampling;
A timing detection unit configured by a two-stage matched filter of a chip matched filter and a frame matched filter, and detecting a reception timing based on a digital signal output from the A / D conversion ;
Equipped with,
The chip matched filter calculates a correlation between the input digital reception signal and a predetermined template signal, and recognizes that a correct transmission pulse signal has arrived if the correlation value exceeds a threshold value. Outputs the presence / absence of pulse and reception timing detection results to the frame matched filter.
A wireless communication apparatus. The oversampling A / D converter is a 1-bit A / D converter that converts a signal into a digital signal, and an N parallel counter that counts the number of occurrences of 1 every N samples in parallel and outputs it in units of frames. Composed,
The wireless communication apparatus according to claim 1. The frame matched filter performs a correct / incorrect determination of the received frame by taking a correlation value with the spreading code, and finally outputs a reception timing when the received frame is determined to be correct, If it is determined that the threshold value is instructed to the chip matched filter,
The wireless communication apparatus according to claim 1 .

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